Idle Trouble After Storage

[mdiggs]

I need some advice on an idle issue. My 68 Ski Sporter (Ford 351) had been stored for 5 years. We dewinterized it, checked for leaks, got it running.
Here's the catch: It runs like a dream above 1800 rpms, but it just doesn't want to idle. My father thinks it is just the old gas (for some reason, he stored it with a full tank!), but I'm wondering whether the old fuel will do damage and also whether there is something else I should check. Buizilla in another thread mentioned carburetor problems (cracked power valves) and needing to rebuild it, but I'm wondering whether (hoping?) that is overkill as a first step to diagnosing the problem.
Questions:
1. Should I siphon off the old gas and start fresh?
2. Should I run as much of the old gas out as I can and add new?
3. Should I have the carburetor checked in case it's not the gas?
This is my first few months wit the boat, and I'm not a mechanic, so I wondering whether the behavior warrants taking it to a shop or whether I should just add new gas and fiddle with the idle on my own.

[hardcrab]

add some dry gas (alcohol), run out the tank. If it's no better, rebuild the carb.

[RedDog]

I would start by adding some octane boost / fuel system cleaner to the gas you have. Then take the spark arrestor off and spray carb cleaner in all of the ports /jets/etc. If that doesn't get it after a few tries, then try changing the spark plugs. After that - get back to us.

[mrfixxall]

I would start by adding some octane boost / fuel system cleaner to the gas you have. Then take the spark arrestor off and spray carb cleaner in all of the ports /jets/etc. If that doesn't get it after a few tries, then try changing the spark plugs. After that - get back to us.


me personally i would drain the tank,,old fuel = no octane which can distroy the engine...do what everbody said about the carb spray..also after you get fresh 93 octane in the tank it wouldnt hurt to dump 2 bottles of seafoam in the tank,,ive seen this stuff work wonders on carbs...then clesn the carb with carb spray,, now when you have the engine warm runnung on the hose disconnect the throttle linkage from the carb and rev the motor to 3000 rpm and snap the choke shut until it almost dies,,i usually do this several times whyle feathering the throttle by hand so it doesnt die..doing this wil suck all the crap out of the idle circuit in the carb.....

[98shovel]

after that if a holley and been sitting dry the powervalve will be junk

[mdiggs]

Thanks, everyone. I'll drain some gas, get new, add some of the fuel cleaners recommended and see what happens. Cleaning the carb and changing spark plugs I can handle this year, but if I need to rebuild the carb, I'll probably winterize it again and do that next spring. :( Ah, this is the fun part of being a boat owner.
:crossfing: